Variable height jack



Feb. l5, 1944. E, p GRlME 2,341,542

y VARIABLE HEIGHT JACK Filed May 18, 1942 l] im mgm Patented Feb. 15, 1944 VARIABLE HEIGHT JACK Edward P. Grime, Huntington Park, Calif., assignor to Malahar lMachine Company, a oopartnership composed of Edward P. Grime and W. F. Foy

Application May 18, 1942, Serial N0. 443,339

6 Claims. (Cl. 2514-93) This invention relates to a jack or shore, and While the invention is capable of application in the construction of a jack `or shore for any purpose, the invention is illustrated in the following specication and in the drawing, as applied to a type of'jack or shore that is particularly useful either for lifting an aeroplane off the ground by means of two of these jacks applied to the under side of the wings on opposite sides of the fuselage, or else to operate as a shore applied in a similar manner to maintain such an airship in an upright position.

The servicing of an yaeroplane requires, among other things, that the plane be raised from the ground in order to check or change wheels or tires, and to check, inspect and repair retractable and/or landing gear apparatus. In such service work it frequently happens that, while in an elevated position, the motor or motors will be operated. Such operation obviously exerts a forward or horizontal thrust against the supporting jack or shore. Moreover, a horizontal thrust occurs, also, Vnot infrequently, While the plane is being supported on the jack, from strong winds or wind storms.

Specications for aeroplane jacks, therefore, require that the jacks used for, supporting aeroplanes, shall not only meet minimum load tests that develop vertical stresses in the structure, but also require that the frame of the jack shall have sucient stability to resist the horizontal thrust developed by the propeller, or propellers, of the aeroplane when the motors are being run at a low speed 'as may be necessary during servicing them.

There is considerable variation in the requirements of such a jack as regards the point; above the ground at which the jack must apply its lifting force. For example, two aeroplanes of diierent type, may each have a 90 inch wing height, and one of these types m-ay require a 48 inch jack ram fully extended to provide for adequate servicing, while the other may need only a 36 inch extension jack. Other conditions occur, for example, in which a, plane having a wing height of 110 inches may require a jack lift of only 30 inches, while another type of plane having a wing height of 60 inches may require a jack extension lift of 48 inches. y One of the objects of this invention is -to provide a variable height jack which will meet requirements such as those indicated above.

A further object of the invention is to provide a variable height jack in which the cylinder or body of the jack is supported in such a way that its elev-ation above the ground can be altered to adapt it to use with different types of aeroplanes, that is to say, to provide a jack having a frame which can readily be set up las aV low jack frame, and also as a jack frame to accommodate aeroplanes in which the starting point of the lift will be elevatedto different levels as compared with the starting point of the lift when the jack is set up as a low jack.

In its general construction, the jack includes a body member carrying a ram or plunger which is supported upon an adjustable frame, and one of the objects of the invention is to provide a simple construction for the frame, which can be readily adapted to support the body member of the jack in a low position `lust above the ground line, and also in a plurality of different elevated positions; and to accomplish this without greatly altering the angle or inclination of the legs of the frame to a vertical line.

A further object of the invention is to provide simple means for extending or lengthening the legs of the frame, and to provide means for resisting the horizontal stresses in the legs at or near the ground line, capable of being used with different variable heghth setups of the frame.

Further objects of the invention will appear hereinafter.

The invention consists in the novel parts and combination of parts to be described hereinafter, all of which contribute to produce an eflicient variable height Jack.

A preferred embodiment of the invention is describedin the following specication, while the broad scope of the invention is pointed out in the appended claims.

In the drawing:

Fig. 1 is a side elevation of a jack or shore embodying my invention and illustrating the jack structure set up to form a high jack, that is to say. a jack adapted to support an aeroplane wing located at considerable elevation above the ground.

Fig. 2 is a side elevation with certain parts broken away, illustrating the jack structure set up as a low jack in which the supporting head of the jack is maintained at a relatively low elevation above the ground. In this view certain parts are broken away and shown in cross-section.

Fig. .3 is an ideal sectional plan taken about on the line -3-3 of Fig. 1, to further illustrate the construction of the braces near the ground line for resisting horizontal components of stresses existing and developed longitudinally of the legs of the frame.

Fig. 4 is a fragmentary section taken in a vertical plane, and illustrating onemanner in which a joint may be formed between an extension leg and the upper leg member.

Fig. 5 is a section taken about on the line 5-5 of Fig. 4, and further illustrating details of the construction illustrated in Fig. 4.

Fig. 6 is a horizontal section taken about on the line 6-6 of Fig. 1, and illustrating details at the upiorting head or collar at the upper end of the Fig. 7 is a view similar to Fig. 3. but illustrating a modified embodiment of the tie bars for connecting the lower ends of the legs.

Referring more particularly to the parts, and particularly to Fig. 2, this view illustrates the jack set up as a low jack, while Fig. 1 illustrates the jack set up as a high jack. Referring now to Fig. 1, the jack involves the use of a. body member I which, in the present instance, is in the form of a duid-operated cylinder in which the piston 2 indicated in dotted lines, is forced upwardly by the iiuid pressure so as to extend the jack plunger 3 above the upper end of the jack frame that in the present instance, is surmounted by a head or collar 4. In the present instance, the plunger` 3 is formed with threads as indicated, on which a nut 5 is mounted. The fluid pressure may be applied to the lower end of the cylinder by providing a small pump (not illustrated) carried on the base plate '6 of the cylinder; or, if desired, fluid pressure could be supplied to the lower end of the cylinder through a hose. In the operation of jacks of this type, the nut 5 when seated on the collar 4, supports the load on the head 'I of the jack, and will maintainthis head in a iixed position regardless of whether there is any leakage or loss of pressure under the piston 2.

The jack frame includes a plurality of legs which are attached to the collar 4 preferably by a joint employing a pivot pin or bolt 8 corresponding to each leg member 9. There may be as many of these leg members 9 as desired, but in the present instance, the frame is illustrated as a tripod. The upper end of the body member or cylinder I, includes a neck I which is rigidly secured in the collar 4, and just below this neck the construction may include an upper head II which suspends the lower head or base 6 of the cylinder 0n tie rods I2.

In accordance with this invention, I provide a plurality of links I3 corresponding respectively tov the different leg-members 9. These links may extend at any inclination, and from any point on the body I, out to the leg-members. In the low jack construction illustrated in Fig. 1, these links extend upwardly from a point near the lower end of the cylinder, and connect at their outer ends to the leg-members. In the high jack setup the links I3 are connected to the lower portions of the leg members 9, and in this high jack setup, extension legs` I4 are provided that connect to the lower ends of the leg-members 9. In order to enable the links I 3 to be used in these two positions and to adapt the construction to form a low jack or a high jack, I prefer to provide a sliding sleeve I5 on each leg-member. These sleeves I5 are preferably in the form of split sleeves with lugs I6 provided with clamping bolts I'I which may be tightened up to clamp the sleeves rigidly on the leg-members. If desired,- the outer ends of the links I3 can be held loosely on the bolts I 1 to permit the links to have the necessary pivotal movement around these bolts in transforming the jack from one type to the other.

The upper ends of the leg-members are tted in between lugs 8B and are maintained in the same radial plane at all times. The legs, of course, are 120 apart as viewed in plan.

In the present instance, I prefer to use each split sleeve I5 to form a socket I8 at the lower ends of the leg-members 9 to receive the upper ends of extension legs I4 (see Fig. 4). In order to accomplish this, of course, it is merely necessary to loosen up the bolts when the sleeves I5 are in the position shown In Fig. 2, and slide the sleeves down to the lower ends of the leg-members 9 s0 that they will project beyond lthe lower ends of the leg-members somewhat as illustrated in Fig. 4, and then the bolts I1 are clamped up to secure the sleeves in this position and form a fixed socket I8. The lower end of the sleevemay be threaded if desired. to enable the extension leg I4 to be screwed into it. At the lower end of each leg-member 9 as illustrated in Fig. 2, a split socket I9 is provided, with a bolt to enable it to be clamped to the leg-member, and it has a lug at its end pivotally mounted between similar lugs 20 by means of a pin 2I. These lugs 20 project up from a base or footplate 22.

In transforming the jack from a low jack to a high jack, the socket I9 is disengaged from the leg-member 9, and is clamped onto the lower end of the extension leg I4. vThreading of the sockets I9 is permissible but not preferable. In any case the socket should be equally well attachable to the lower end of the leg-member 9 and the extension leg I4.

The base plates or foot-plates 22, rest upon the ground or cement pavement. In order to resist horizontal components of longitudinal thrusts exerted in the legs due to the load, I prefer to provide adjustable tie-bars or links 23 connecting the plates 22. In order to enable these tie-bars to be quickly adjustable, I prefer to construct them in the form of two overlapping straps 23a and 23h. (See Fig. 3.) One of these straps may be provided with spaced bolt holes 24 to align with holes in the opposite strap member so as to receive clamping bolts 25 to secure these clamping straps together. These bolt holes would be positioned so as to come into alignment with each oth/er for the different A base spreads corresponding to different heights for the jacks. In this connection, of course, it should be understood that the extension legs I4 may be of different lengths so as to give diiierentl heights to the jack to meet various specifications. The outer ends of the straps 23a and 23b are pivotally mounted between the lugs 26 that project fromthe base plates 22. Removable bolts can be used for this purpose, enabling the parts of the jack to be shipped in a knocked down condition for quick assembly.

Means is provided on the body member I -for connection to the inner ends of the links I3, and in the present instance, this means is in the form of a, split sleeve or collar 29 that can be rigidly clamped to the barrel of the jack in any position. In Fig. 2 this collar is secured to the barrel near its lower end. This sleeve is Drovided with lugs 30 to which the inner ends of the links I3 are pivotally attached.

The collar 4 and the body I are rigid with each other so that the body-member cannot swivel on its own longitudinal axis. This insures that the lugs 30 will always maintain themselves in the same radial plane with the lugs I6, thereby assisting in holding the legs spaced equally apart.

In Fig. 7 I illustrate a modification of the construction for the base of the trame that may be employed instead of that illustrated. in Fig. 3. 'In the construction illustrated in Fig. 1, a center ring 3I is provided with double lugs 32 spaced apart on the ring, and these lugs attach t 334 formen of two overlapping sections 33a and 33h that are adjustably secured together by .djustable radial tie rods or tie bars bolts 34. The outer sections 33a of these tie rods would, of course, secure to the foot-plates ,35 in the same manner as the tie rod sections 23a are secured to the foot-plates 22.

In order to prevent the upper end of the head l from injuring the under side of an aeroplane wing or other part supported by the jack, the head 'l may be provided with a saddle plate lq if desired, with a cushioning material on its upper side.

Many other embodiments of the invention may be resorted to without departing from the spirit of the invention.

' What I claim is: 1. In a jack or shore, variable for height, the combination of a substantially upright bodymember, a plunger associated with the bodymember and extensible upwardly therefrom, a plurality of leg-members with joint connections connecting the same to the upper portion of the body-member, a link corresponding to each legmember, a sleeve having a joint connection with each link and secured to the lower end of each leg-member so as to project beyond the same and form a socket o receive the upper end of an extension leg, to cooperate in forming a high jack, said sleeves capable of sliding upwardly' on the leg-members and having means for securing them in a, more elevated position on the leg-members to form a low jack, and means including joint connections corresponding to the diierent links for securing the links to the bodymember.

2. In a jack or shore, variable for height, the combination of a substantially upright bodymember, a plunger associated with the bodymember and extensible upwardly therefrom, a plurality of leg-members with joint connections connecting the same to the upper portion of the body-member, a link corresponding to each legmember, a sleeve-pn each leg-member having a joint connection with each link, mea /for securing each sleeve to the lower end o its corresponding leg-member so as to project beyond the same and form a ksocket to receive the upper end of an extension leg to cooperate in forming a high jack, said sleeves capable of being loosened and slid upwardly to a, more elevated position on their leg-members and re-securbd there to form a low jack; and means including joint connections corresponding to the diierent links for securing the links to the body-member.

3. In a jack or shore, variable for height, the combination of a substantially upright bodymember, a plungerv associated with the bodymember and extensible upvfardly therefrom, a. plurality of leg-members with joint connections connecting the same to the upper portion of the body-member, a link corresponding to each legmember, a sleeve on each leg-member having a joint connection with each link, means for securing each sleeve to the lower end of its corresponding leg-member so as to project beyond the same and form a socket to receive the upper end of an extension leg to cooperate in forming a high jack, extension legs received in the said sockets to support the body-member in a relatively elevated position/K said sleeves capable of being loosened and slid upwardly on their legmembers and re-secured to the same in an elel vated position to form a low jack; and means including joint connections corresponding to the different links for securing the links to the bodymember.

4,'In a jack or shore, variable for height, the combination of a substantially upright bodymember, a plunger associated with the bodymember and extensible upwardly therefrom, ya plurality of leg-members with joint connections connecting the same to the.upper portion of the body-member, a. link corresponding to each legmember, a sleeve on each leg-member' having a joint connection with each link, means for securing each sleeve to the lower end of its corresponding leg-member so as to project beyond the same and form a socket to receive the upper end of an extension leg tocooperate in forming a high jack, extension legs received in the said sockets to support the body-member in a relatively elevated position, said sleeves capable of being loosened and slid upwardly on their legmembers and re-secured to the same, in an elevated position to form a low jack; means including joint connections corresponding to the different links for securing the links to the bodymember, base members supporting the extension legs, and adjustable tension members connecting the base members for resisting the horizontal components of the stresses exerted in the extension legs, said adjustable tension members capable of adjustment to adapt the same to cooperate with base members supporting extension legs of diierent lengths and corresponding to jacks of different heights. v

5. In a jack or shore, variable for height, the combination of a substantially upright bodymember, a plunger associated with the bodymember and extensible upwardly therefrom, a plurality of leg-members with joint connections connecting the same to the upper portion of the body-member, a sleeve on each leg-member, a plurality of links located in substantially radial planes respectively, pivotally connected to the lower portion of the body member, each sleeve having .a joint connection with a corresponding link, each sleeve having means associated therewith for enabling the sleeve to be held xed on its leg-member adjacent the lower end of the leg-member in adapting the above named parts for use in a high jack, said sleeves being also capable of assuming a position at an intermediate point on the leg-members with the links inclining upwardly toward their outer ends in forming a low jack structure.

6. In a jack or shore, the combination of a frame including a collar and a plurality of legmembers, each leg-member having a pivot joint connection to said collar, a `foot-plate corresponding to each leg-member and having a disconnectible connection thereto, a body-member located just below said collar and supported thereby, a link pivotally connected to each legmember and to the body-member, extension legs with means for eiecting a joint connection between the same andusad leg-members, the lower ends of said extension` legs having means for attaching the same to said foot-plates and extensible links attached to the foot plates and connecting the same for resisting the radial component of the load-thrusty in each leg.

EDWARD P. GRIME 

